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Marginal sulcus

The marginal sulcus is an important anatomical landmark of the medial surface of the cerebral hemisphere, found near the cingulate gyrus. It plays a crucial role in demarcating key cortical regions and serves as an essential reference point in both neuroanatomy and neuroimaging. Understanding its synonyms, function, vascular supply, and imaging characteristics is fundamental for radiologists, neurologists, and neurosurgeons.

Description:

  • The marginal sulcus is the terminal segment of the cingulate sulcus.

  • Located on the medial aspect of the cerebral hemisphere, just posterior to the paracentral lobule.

  • It ascends vertically towards the superior margin of the hemisphere, often forming an “inverted L” shape.

  • Serves as an anatomical boundary between the paracentral lobule and the precuneus.

Synonyms:

  • Marginal branch of the cingulate sulcus

  • Marginal ramus of the cingulate sulcus

  • Ramus marginalis sulci cinguli (Latin)

Function:

  • Primarily serves as an anatomical landmark rather than having a direct functional role.

  • Helps delineate the boundaries of the paracentral lobule (which contains parts of the primary motor and sensory cortices related to the lower limb).

  • Important in surgical planning and neuroimaging for orientation and localization.

Arterial Supply:

  • Supplied mainly by branches of the anterior cerebral artery (ACA), especially the pericallosal and callosomarginal arteries.

  • These vessels run parallel to the cingulate sulcus and provide blood to the adjacent cortex.

Venous Drainage:

  • Drains into the superior sagittal sinus via superficial cortical veins.

  • Venous blood from this region may also flow through the cingulate vein, which parallels the cingulate sulcus.

MRI Appearance:

  • T1-weighted Images:

    • The marginal sulcus appears as a linear hypointense (dark) groove.

    • Clearly separates cortical gray matter regions on the medial brain surface.

  • T2-weighted Images:

    • Sulcus is filled with cerebrospinal fluid (CSF), which appears hyperintense (bright).

    • Provides a clear demarcation from the surrounding cortical tissue.

  • FLAIR Images:

    • The sulcus is seen as a hypointense (dark) line because CSF signal is suppressed.

    • Useful for distinguishing sulcal spaces from pathological lesions (e.g., edema or gliosis).

CT Appearance:

  • The marginal sulcus is seen as a hypodense (dark) linear structure due to the presence of CSF.

  • Best visualized in coronal or sagittal reformatted images, especially in the absence of brain atrophy.

  • Subtle in younger patients; becomes more prominent with age or in conditions causing cortical atrophy.

MRI images

Marginal sulcus MRI 3T axial image

MRI images

Marginal sulcus MRI 3Tsagittal image